Powered turnaround for a coil lift and transfer car and the like

ABSTRACT

We disclose a carriage structure for conveying coils and the like, which structure comprises a wheel-mounted platform, a lift housing carried on the platform, a lift structure slidably mounted in the housing and engaging lift means mounted within the lift housing so that the lift structure is raised and lowered upon actuation of the lift means. The lift structure includes an upper projection shaped for closely fitted insertion into an opening in an external load support. Load bearing platen is rotatably mounted adjacent the upper surface of the projection and substantially within the confines thereof, and a turnaround mechanism for the platen is mounted within the confines of the projection and in operative engagement with the platen. In certain applications, a thrust bearing is mounted between the platen and adjacent surfaces of the projection. The platen and the projection surfaces can be shouldered to accomodate the bearing. The turnaround mechanism can b both double-acting and bidirectional for the application of maximum torque to the platen.

United States Patent Petros et al.

[ 51 May 23, 1972 [54] POWERED TURNAROUND FOR A COIL LIFT AND TRANSFER CAR AND THE LIKE [72] Inventors: Andrew J. Petros; Clement S. Rybar, both of Pittsburgh, Pa.

[73] Assignee: Mesta Machine Company, Pittsburgh, Pa.

[22] Filed: July 22, 1969 [2]] Appl. No: 844,216

3,434,606 3/1969 Asamura 14/38 CC 659,707 10/1900 Stephens... 104/46 2,957,362 l0/l960 Kelm ..lO4/35 X 3,186,655 6/1965 Huffington et al ..242/79 Primary Examiner-Gerald M. F orlenza Assistant Examiner-Frank E. Werner Att0rneyDon J. Smith [57] ABSTRACT We disclose a carriage structure for conveying coils and the like, which structure comprises a wheel-mounted platform, a lift housing carried on the platform, a lift structure slidably mounted in the housing and engaging lift means mounted within the lift housing so that the lift structure is raised and lowered upon actuation of the lift means. The lift structure includes an upper projection shaped for closely fitted insertion into an Opening in an external load support. Load bearing platen is rotatably mounted adjacent the upper surface of the projection and substantially within the confines thereof, and a turnaround mechanism for the platen is mounted within the confines of the projection and in operative engagement with the platen. In certain applications, a thrust bearing is mounted between the platen and adjacent surfaces of the projection. The platen and the projection surfaces can be shouldered to accomodate the bearing. The turnaround mechanism can b both double-acting and bidirectional for the application of maximum torque to the platen.

1 1 Claims, 6 Drawing Figures iii PATENTED Y 23 I972 PATENTl-inmzs m2 3.664.518

sum 5 OF 6 POWERED TURNAROUND FOR A COIL LlFl AND TRANSFER CAR AND THE LIKE The present invention relates to a powered turnaround or pivot device for use in a restricted space, and more particularly to a device of the character described which can be mounted within the space limitations of the superstructure of a coil lift or transfer car and the like.

In the operation of various types of strip rolling mills or processing lines, the strip coils must be moved between various pieces of equipment frequently including an inspection station. The several required transfers of the strip coils are accomplished with use of a coil lift and transfer car. As the strip coils are moved among the various components of the rolling mill or to an inspection station, they may require turning or reorienting while supported on the transfer car. Owing to the large masses of the strip coils, lifting, transferring and turning or re-orienting of the strip coil is a cumbersome and time-consuming procedure. 7

Many types of existing transfer cars are incapable of turning the coils loaded thereon and the strip coils must be removed from the transfer car and then replaced in re-oriented position. This involves the use of additional coil handling apparatus. Frequent handling adds, of course, to the possibility of coil damage.

In other known coil cars and similar coil handling apparatus, part or all of the apparatus is pivoted with the coil. As a result, a large and cumbersome pivot structure is required and a considerable area is required in the vicinity of the coil handling apparatus to permit pivoting of both the coil and part or all of the apparatus. Coil cars are also known which have a rotatable superstructure for turning or re-orienting the coil. The superstructure, however, must be withdrawn from its insertion into or between the rolls of inspection equipment and other components of the rolling mill, before the coil and the superstructure can be turned. Space as well as time is necessarily wasted in this conventional operation.

in modern rolling mills space limitations prevent or render difficult the use of the aforementioned types of coil handling apparatus. Some of such apparatus is typified by the U.S. Pats. to Smith No. 2,586,874 and Naugle et al. No. 1,740,260. In each of these references part or all of the coil handling apparatus must be turned with the coil. The Smith apparatus suffers from an additional disadvantage in that the inner wraps of i the coils are engaged by the coil handling device.

We overcome these disadvantages by providing a compact turnaround or pivot mechanism which is capable of developing the tremendous torques required in coil handling operations but which is of such size that it can be conveniently mounted in a restrictive space in applications where area considerations are paramount. For example, the turnaround can be mounted in the top area of a C-frame or of the superstructure forming part of the coil lift and transfer car illustrated herein. With our arrangement only the coil itself and a relatively small angularly displaceable member of the car are pivoted or re-oriented when the turnaround mechanism of the transfer car is operated. As no substantially projecting component of the transfer car is pivoted with the coil, the space requirements of the coil turning or re-orienting operation are considerably reduced, as our coil car does not require withdrawal from the inspection station or other coil handling equipment. The use of the C-frame, in certain applications, with the turnaround mechanism and the angularly displaceable member largely confined therein, allows use of the transfer car in otherwise inaccessible locations.

In an illustrative arrangement of our turnaround device we utilize a pair of double-acting, movable cylinders which are provided with rack means for cooperating with an output pinion for pivoting purposes. We also provide a unique shock absorption arrangement which is mounted in each of the cylinders for cooperation with a stationary rod on which each cylinder rides. Means are provided for conducting a suitable hydraulic fluid through the rod for actuating the cylinders.

We are aware of a number of previous and known devices for producing output torques, for example the U.S. Pats. to

Rudd et at. No. 3,190,190; Cederleaf No. 3,101,639 and Steiner No. 2,844,127. The Steiner and Rudd devices employ oppositely moving racks engaged with a pinion and connected respectively to double-acting pistons. There are no particular shock-absorbing means provided other than the end walls of the stationary cylinders in which the pistons move. Because of the tremendous loads encountered with coil handling operations, the Steiner and Rudd devices obviously would be inappropriate for this and similar applications. The Cederleaf mechanism uses a pinion and single rack which is reciprocated by a moving member which is partially mounted upon a stationary rod and partially on a surrounding cylinder. Here again, there are no shock-absorbing means and the device is even less suitable for handling very large loadings than the Rudd et al and Cederleaf mechanisms.

With the compact coil lift and transfer car structure made possible by our invention, a coil or other heavy load can be conveniently lifted from a saddle type conveyor or other pallet type apparatus by means of the C-frame lift forming part of the transfer car. As the C-frame does not have to be pivoted, adequate space remains for operation of the equipment from which the coil is being removed by the transfer car.

The patent to Senn U.S. Pat. No. 2,402,848 also is of interest in that a moving cylinder is disclosed relative to a stationary piston or piston rod. Senn however does not disclose the particular arrangement employed by our mechanism for inducting hydraulic fluid or the like into the moveable cylinder. Senn likewise does not disclose a pair of double-acting cylinders nor an adequate shock-absorbing means. Finally, the Senn structure is a fluid motor and does not possess turnaround or pivot capability.

Shock-absorbing means are, of course, disclosed in Aslan U.S. Pat. No. 3,247,767 and in many other references. Aslan typically, does not disclose a turnaround or pivot device, nor does he disclose the particular unique shock-absorbing means of our turnaround mechanism which is unexpectedly capable of severe loadings.

None of the cited references shows a rotatable platen and thrust bearing forming part of the turnaround and shaped to support a strip coil or other extremely heavy load.

We overcome these disadvantages of the prior art and accomplish the aforementioned desirable ends by providing a carriage structure for conveying coils and the like, said structure comprising a wheel mounted platform, a lift housing carried on said platform, a lift structure slidably mounted in said housing and engaging lift means mounted within said lift housing so that said lift structure is raised and lowered upon actuation of said lift means, said lift structure including an upper projection shaped for closely fitted insertion into an opening in an external load support, a load bearing platen rotatably mounted adjacent the upper surface of said projection and substantially within the confines thereof, and a turnaround mechanism for said platen mounted within the confines of said projection and in operative engagement with said platen.

We also desirably provide a carriage structure for conveying I coils and the like, a lift structure elevatably mounted on said carriage structure, lift means supported on said carriage structure for raising and lowering said lift structure, said lift structure including an upper projection shaped for closely fitted insertion into an opening in an external load support, a load bearing pivot member rotatably mounted on said projection adjacent the upper surface thereof and disposed substantially within the confines thereof, a thrust bearing confined between said pivot member and an adjacent shouldered portion of said projection, and a turnaround mechanism for angularly displacing said pivot member, said tumaround mechanism being mounted within the confines of said projection and in operative engagement with said pivot member.

We also desirably provide a turnaround mechanism for a coil carriage and the like, said mechanism comprising a housing defining a pinion cavity and a pair of rack cavities interconnected therewith, a pinion rotatably mounted within said pinion cavity and a pair of reciprocatable cylinders having rack means thereon mounted respectively within said rack cavities and a pair of support rods stationarily mounted on said housing and protruding respectively on the protruding portions of said support rods and being sealed thereto adjacent one end of said cylinder.

We also desirably provide a similar turnaround mechanism wherein shock-absorption means are mounted in the other ends of said cylinders for shock-absorbing engagement with the protruding portions respectively of said support rods when the protruding portion of the associated support rod is substantially fully inserted into the associated cylinder.

We also desirably provide a similar turnaround mechanism wherein each of said rods is provided with longitudinally extending passage means for supplying actuating fluid to said cylinders.

We also desirably provide a similar turnaround mechanism wherein end portions of said supporting rods are tapered for increasingly closely fitting engagement into dash pots forming part of said shock-absorption means respectively.

Although described primarily in its rolling mill application, it will be understood that our invention is not limited to this use and is of general utility in transporting and/or re-orienting rather heavy loads.

During the foregoing discussion, various objects, features and advantages of the invention have been set forth. These and other objects, features and advantages of the invention together with structural details thereof will be elaborated upon during the forthcoming description of certain presently preferred embodiments of the invention and presently preferred methods of practicing the same.

In the accompanying drawings we have shown certain presently preferred embodiments of the invention and have illustrated certain presently preferred methods of practicing the same, wherein:

FIG. la (lb) is an elevational view of one arrangement of coil lift and transfer car arranged in accordance with our invention;

FIG. 2 is a vertically sectioned view of the transfer car of FIG. 1 and taken along reference line 1 lII thereof;

FIG. 3 is an enlarged sectional view of the superstructure of the transfer car of FIGS. 1 and 2 and showing in detail the load bearing platen and turnaround mechanism thereof; and

FIG. 4a (4b) is a horizontally sectioned view of the turnaround structure as shown in FIG. 3 and taken along reference line IIIIIl thereof.

With more particular reference to FIGS. 1 and 2, a coil transfer car or carriage includes a wheel mounted platform 12 for movement along a pair of track members 14. A lift or cylinder housing 16 is depended from the platform 12 and is shaped in this example for movement along and within a trough or pit 18 formed between the tracks 14. A relatively large plunger or lift structure 20 is closely fitted within the cylinder housing 16 for vertical movement therewithin. To effect such movement means such as cylinder 22 is mounted upon a platform 24 secured in the lower end of the cylinder housing 16, and a protruding piston rod 26 of the cylinder arrangement 22 bears against a similar platform 28 mounted near the upper end of the plunger 20.

A C-frame 30 or other suitable superstructure is mounted on the platform 28 and hence on the piston of the pistoncylinder arrangement 22, 26 (FIG. 2), and is constructed for supporting the weight of a coil or other heavy load supported on a platen 32 rotatably mounted on the C-frame or projection 30. In this arrangement the platen 32 is mounted upon a suitable thrust bearing 34 and on a stepped pivot structure 36 of which drive pinion 38 forms a component part. The platen 32 includes in this example a pair of load bearing plates 40, 42 which are disposed on the upper surface of the platen 32 at a relatively large obtuse angle. The platens 40, 42 form a shallow V-trough which is capable of supporting and retaining a relatively large diameter coil. The platen 32, therefore, can be lifted bodily from the C-frame for maintenance purposes without disconnecting any engaging components.

As shown more particularly in FIG. 2 the C-frame 30 is shaped for closely fitting insertion within coil handling equipment, in this example between a pair of inspection station rolls 44. As the entire C-frame 30 need not be pivoted in order to re-orient a coil 46 supported thereon it is no longer necessary to move the coil carriage 10 away from the inspection station and back again in order to turn the coil 46. Instead the cylinder 22 is actuated to raise the C-frame 30 and the coil 36 supported thereon to their chain outline positions such that the coil 46 clears the inspection rolls 44. At such time the turnaround mechanism 48 is actuated to pivot the platen 32 and coil 46 after which the coil 46 can be lowered to the inspection rolls 44. For maximum loading the piston 26 desirably engages the C-frame 30 including its platform 28 substantially coaxially of the platen 32, as shown in FIGS. 1A and 2.

An exemplary arrangement of the turnaround mechanism 48 is shown in detail in FIGS. 3 and 4 of the drawings. The pinion 38 is secured to the pivot 36 for rotation therewith in a conventional manner such as by key or spline S0. The rather large torques required are delivered to the pinion 38 by a pair of racks 52, 54 formed respectively on a pair of double-acting reciprocatable cylinders 56, 58. The cylinders 56, 58 are movable within a pair of interconnected chambers 60, 62 formed within a housing 64 of the turnaround mechanism 48. The chambers 60, 62 are interconnected by passage 66 partially surrounding the pinion 38 and are otherwise sealed within the housing 64. Accordingly, a suitable lubricant can be employed to fill the chambers 60, 62 to provide adequate lubrication for the racks 52, 54, pinion 38 and other moving components.

The reciprocatable cylinders 56, 58 which are generally circular in cross section for example, are supported throughout their paths of movement by a pair of stationary rods 68, 70 and by substantially semi-cylindrical liners 72, 74 secured to the adjacent wall surfaces of the associated generally circular cylinder cavities 60, 62 as better shown in FIG. 3. The liners 72, 74 are formed from a suitable material such as bronze or other bearing material and are disposed to absorb the outward radial forces resulting from engagement of the rack and pinion teeth. The back-up liners 72, 74 are mounted on those wall surfaces of the cavities 60, 62 which are remote from the pinion 38.

The inward or rod end of each cylinder 56 or 58 is sealed to the associated rod 68 or 70 by suitable packing, such as chevron seal 76 and annular retainer or compression member 78. The opposite or blank end of each cylinder is closed by a dash pot 80 of unique construction as set forth below, which in this example threadedly engages the cylinder end. Loosening of the dash pot 80 is prevented by set screw 82. The blank end of each cylinder is sealed with a suitably disposed O-ring 84. In consequence, it is not necessary to seal the outer surface of the cylinders 56, 58 to the adjacent wall surfaces of the cylinder wall cavities 60, 62.

Each of the stationary supporting rods 68,70 is inserted into the associated cylinder cavity 60 or 62 through a connecting passage 86 or 88. The outward end portions of the rods 68, 70 are thickened for relatively close fitting engagement within the connecting passages 86, 88 respectively. The remainder of the rods 68,70 are of reduced diameter relative to the passages 86, 88 to permit a limited flexure of the rods to compensate manufacturing tolerances, abrupt load changes, and the like. The thickened end portions 90 of the rods 68, 70 are provided with suitable O-rings 92 whereby the connecting passages 86, 88 are sealed, together with the adjacent ends of the cylinder cavities 60, 62. The other ends of the cavities are closed and sealed by their end caps 94 and O-rings 96.

To reciprocate the cylinders 56, 58 each of the support rods 68 or 70 is provided with passage means, such as a pair of longitudinal fluid passages 98, into which pressurized fluid such as a hydraulic medium is introduced through ports 102, 104 respectively. A suitable branched conduit system, denoted generally at reference character 106 is coupled to the ports 102, 104. The conduit system 106 is connected to a suitable source (not shown) of such fluid.

The longitudinal rod passages 98, 100 open into the spaced enclosed between the associated cylinder and rod at points on either side of an annular partition 108 which is secured near the otherwise free end of each supporting rod 68 or 70. in this arrangement the annular member 108 threadedly engages the associated rod and is affixed at this position by set screw 110. Each cylinder 56 or 58 is sealed at its passage over the partition 108 by an appropriate seal such as O-ring 112. In this arrangement the longitudinal rod passages 98 communicate with the rod ends of the cylinders 56, 58 through orifices 114, while the other longitudinal rod passages 100 similarly communicate with the blank ends of the cylinders through orifices 116. At the travel limits of the cylinders 56, 58 annular recesses 118 and 120 are formed in the partitions 108 and in the rod ends of the cylinders to avoid blocking the orifices 114, 116 respectively. An O-ring 113 is interposed between each partition 108 and the associated supporting rod 68 or 70 to seal the cylinder compartments formed by the partition.

The use of the dual passages 98, 100 and the partitions 108 of each supporting rod affords a double-acting characteristic to the movement of each cylinder 56 or 58. The partition 108 along with the rod seal or packing 76-78 and associated liner 122 in effect provides a two-point spaced support upon the rod 68 or 70 for each cylinder throughout its path of travel.

As noted previously each of the reciprocatable cylinders 56, 58 is provided with shock-absorbing means 80. With the interconnection between the cylinders 56, 58 afforded by the pinion 38 and the racks 52, 54, the teeth of which in this example are formed integrally upon the movable cylinders, it is necessary to provide shock-absorbing means only at one end of each cylinder. One arrangement of such shock-absorbing means includes the dash pots 80 mentioned previously, each of which includes a central recess 124 for cooperation with a tapered free end portion 126 of the associated supporting rod 68 or 70. As each dash pot 80 is moved by its associated cylinder into close engagement with the tapered rod end 126, the annular opening between the circumference of the end portion 126 and the dash pot recess 124 decreases with further insertion of the rod end. Accordingly, the escape flow rate of the hydraulic fluid entrapped within recess 124 correspondingly decreases for shock-absorption purposes. When the tapered rod end 126 substantially engages the adjacent wall surfaces of the dash pot recess 124, additional shock-absorption is provided by a metering aperture 128 formed in one of the end plugs for the longitudinal rod passages, for example end plug 130. The final escape of fluid entrapped within the recess 124 through the metering aperture 128 (arrow 132) provides the final shock-absorption requirement. Terminal shock-absorption can be afforded, if necessary, by abutting engagement between the dash pot 80 and the adjacent surface of the partition 108 as denoted by reference character 134, as the associated cylinder for example the cylinder 56 comes to rest. At this time, engagement 136 occurs between the blank end of the other cylinder 58 and the cylinder cavity closure 94 which controls the relative position of platen 32 by the enmeshment between the pinion 38 and the racks 52, 54. This engagement 136 can be adjusted by use of one or more shims 137 to align the platen 32 angularly, for example with the remainder of the C-frame.

In the arrangement as shown in FIG. 4, fluid has been introduced under pressure into passage 98 of support rod 68 and into passage 100 of the support rod 70 (arrows 138, 140 respectively) to drive the cylinder 56 to the left and the cylinder 58 to the right to their corresponding limits of travel with attendant rotation of pinion 38 and platen 32. The flow of fluid through the aforementioned channels (arrows 138, 140) induces clockwise movement (arrow 142) of the pinion 38 and of the platen 32 (FIGS. 1-3) to which the pinion 38 is secured. Motion of the pinion 38 and platen 32 in the opposite direction (arrow 144) is induced by releasing the pressure in the aforementioned channels and by introducing fluid under pressure in the remaining channels (arrows 146, 148) of the supporting rods 68, 70 to drive the cylinders 56, 58in their opposite directions until they reach their other limits of travel. In

that time the illustrated positions of the cylinders 56, 58 (FIG. 4) will be reversed.

Owing to the use of a pair of reciprocatable cylinders 56, 58 and a suitable pressurized source (not shown) of hydraulic fluid tremendous torques can be applied to the pinion 38 as required by the inertia of the extremely heavy loads supported by the platen 32. As noted previously, the weight of such loads is borne by the thrust bearing arrangement 34 so that there is no possibility of binding between the pinion 38 or other components of the pivot 36 and the turnaround mechanism housing 64. The pinion 38 is positioned by bushings 150,152 (FIG. 3). Similarly, the use of substantial supporting rods 68, 70, the two-point cylinder supports afforded by the stationary partitions 108 and the cylinder rod end structures, the back up liners 72, 74 endow the mechanism 48 with a capability of absorbing the considerable forces associated with sudden load applications, load reversals and the like. Finally, the structural and operating components of the turnaround mechanism 48 are adequately protected from damage by the use of our unique shock-absorbing arrangement.

From the foregoing it will be apparent that novel and efficient forms of Powered Turnaround for a Coil Lift and Transfer Car and the Like have been described herein. While we have shown and described certain presently'preferred embodiments of the invention and have illustrated presently preferred methods of practicing the same, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the spirit and scope of the invention.

We claim:

1. A carriage structure for conveying coils and the like, said structure comprising a wheel-mounted platform, a lift structure elevatably mounted on said platform, means mounted on said platform for raising and lowering said lift structure, said lift structure including an upper extension, said extension having a projection extending at an angle to said extension and shaped for closely fitted insertion into an opening in an external load support, a load bearing platen rotatably mounted on said projection adjacent the upper surface thereof and disposed substantially within the confines of said projection, and a turnaround mechanism for angularly displacing said platen, said turnaround mechanism being mounted within the confines of said projection and in operative engagement with said platen, whereby said projection said platen and said mechanism can be so inserted.

2. The combination according to claim 1 wherein said upper extension and said projection together define a generally C- shaped configuration and said platen and said turnaround mechanism are mounted on an upper generally horizontally extending arm of said C-shape.

3. The combination according to claim 1 wherein said extension and said projection are shaped such that said lift structure engages said extension at a location substantially directly beneath said platen.

4. The combination according to claim 1 wherein said projection has a cavity in an upper surface thereof, and said platen is rotatably seated in said cavity.

5. The combination according to claim 1 wherein a thrust bearing is confined between said platen and an adjacent internally shouldered portion of said projection.

6. The combination according to claim 5. wherein said platen is provided with a stepped configuration, and a stepped portion thereof is aligned substantially coaxially with at least one of said shouldered portion and said thrust bearing to aid in positioning said platen on said projection.

7. The combination according to claim 1 wherein said projection and said extension are so shaped that said projection extends substantially a horizontal direction.

8. A carriage structure for conveying coils and the like, said structure comprising a wheel-mounted platform, a lift housing carried on said platform, a lift structure slidably mounted on said housing and engaging lift means mounted within said lift housing so that said lift structure is raised and lowered upon actuation of said lift means, said lift structure including an upper projection shaped for closely fitted insertion into an opening in an external load support, a load bearing platen rotatably mounted adjacent the upper surface of said projection and substantially within the confines thereof, a turnaround mechanism for said platen mounted within the confines of said projection and in operative engagement with said platen, said platen including a stepped pivot member, a thrust bearing confined between said platen and a shouldered portion of said projection adjacent said pivot member, said pivot member including a pinion secured thereto for rotation therewith, said turnaround mechanism including a pair of racks engaged with said pinion, and means for reciprocating said racks.

9. The combination according to claim 8 wherein said racks are mounted for reciprocation within a pair of interconnected cavities therefor within said projection and a pair of back up liners are interposed respectively between said racks and those wall surfaces of said cavities remote from said pinion.

10 A carriage structure for conveying coils and the like, a lift structure elevatably mounted on said carriage structure, lift means supported on said carriage structure for raising and lowering said lift structure, said lift structure including an upper extension shaped for closely fitted insertion into an opening in an external load support, a load bearing pivot member rotatably mounted on said projection adjacent the upper surface thereof and disposed substantially within the confines thereof, a thrust bearing confined between said pivot member and an adjacent internally shouldered portion of said projection, a turnaround mechanism for angularly displacing said pivot member, said turnaround mechanism being mounted within the confines of said projection and in operative engagement with said pivot member, bi-directional motive means for angularly displacing said platen in either rotational direction thereof, said motive means including a pair of bi-directional prime movers oppositely coupled to said pivot member and cooperatively energizable for the application of approximately equal turning forces to said pivot member in either rotational direction thereof.

11. The combination according to claim 8 wherein each of said racks abut wall means forming part of said mechanism at one extremity of movement of said racks, and means are provided for adjustably positioning said wall means for angularly aligning said platen. 

1. A carriage structure for conveying coils and the like, said structure comprising a wheel-mounted platform, a lift structure elevatably mounted on said platform, means mounted on said platform for raising and lowering said lift structure, said lift structure including an upper extension, said extension having a projection extending at an angle to said extension and shaped for closely fitted insertion into an opening in an external load support, a load bearing platen rotatably mounted on said projection adjacent the upper surface thereof and disposed substantially within the confines of said projection, and a turnaround mechanism for angularly displacing said platen, said turnaround mechanism being mounted within the confines of said projection and in operative engagement with said platen, whereby said projection said platen and said mechanism can be so inserted.
 2. The combination according to claim 1 wherein said upper extension and said projection together define a generally C-shaped configuration and said platen and said turnaround mechanism are mounted on an upper generally horizontally extending arm of said C-shape.
 3. The combination according to claim 1 wherein said extension and said projection are shaped such that said lift structure engages said extension at a location substantially directly beneath said platen.
 4. The combination according to claim 1 wherein said projection has a cavity in an upper surface thereof, and said platen is rotatably seated in said cavity.
 5. The combination according to claim 1 wherein a thrust bearing is confined between said platen and an adjacent internally shouldered portion of said projection.
 6. The combination according to claim
 5. wherein said platen is provided with a stepped configuration, and a stepped portion thereof is aligned substantially coaxially with at least one of said shouldered portion and said thrust bearing to aid in positioning said platen on said projection.
 7. The combination according to claim 1 wherein said projection and said extension are so shaped that said projection extends substantially a horizontal direction.
 8. A carriage structure for conveying coils and the like, said structure comprising a wheel-mounted platform, a lift housing carried on said platform, a lift structure slidably mounted on said housing and engaging lift means mounted within said lift housing so that said lift structure is raised and lowered upon actuation of said lift means, said lift structure including an upper projection shaped for closely fitted insertion into an opening in an external load support, a load bearing platen rotatably mounted adjacent the upper surface of said projection and substantially within the confines thereof, a turnaround mechanism for said platen mounted within the confines of said projection and in operative engagement with said platen, said platen including a stepped pivot member, a thrust bearing confined between said platen and a Shouldered portion of said projection adjacent said pivot member, said pivot member including a pinion secured thereto for rotation therewith, said turnaround mechanism including a pair of racks engaged with said pinion, and means for reciprocating said racks.
 9. The combination according to claim 8 wherein said racks are mounted for reciprocation within a pair of interconnected cavities therefor within said projection and a pair of back up liners are interposed respectively between said racks and those wall surfaces of said cavities remote from said pinion. 10 A carriage structure for conveying coils and the like, a lift structure elevatably mounted on said carriage structure, lift means supported on said carriage structure for raising and lowering said lift structure, said lift structure including an upper extension shaped for closely fitted insertion into an opening in an external load support, a load bearing pivot member rotatably mounted on said projection adjacent the upper surface thereof and disposed substantially within the confines thereof, a thrust bearing confined between said pivot member and an adjacent internally shouldered portion of said projection, a turnaround mechanism for angularly displacing said pivot member, said turnaround mechanism being mounted within the confines of said projection and in operative engagement with said pivot member, bi-directional motive means for angularly displacing said platen in either rotational direction thereof, said motive means including a pair of bi-directional prime movers oppositely coupled to said pivot member and cooperatively energizable for the application of approximately equal turning forces to said pivot member in either rotational direction thereof.
 11. The combination according to claim 8 wherein each of said racks abut wall means forming part of said mechanism at one extremity of movement of said racks, and means are provided for adjustably positioning said wall means for angularly aligning said platen. 